1. Field of the Invention
This invention pertains generally to agricultural planting equipment.
2. Description of the Prior Art
The efficient production of crops requires that seed planters meet certain primary design objectives which are: creating a furrow having an accurate planting depth and preferably providing soil having a reasonably high moisture content for early germination, accurate seed spacing, and seed and soil contact. This invention is concerned only with the furrow forming aspect of the planter.
A known seed planter utilizes a conventional pair of rotatably mounted, generally flat disk openers that substantially contact each other where the disks enter the ground and which diverge apart rearwardly and upwardly. The disks are supported on a frame which is connected to a tool bar by a parallel bar linkage so that the frame is maintained in a generally horizontal position parallel to the tool bar despite varying ground contours. Individually and pivotally supported from the frame closely adjacent each disk are rotatable gauge wheels with semi-pneumatic tires. Each gauge wheel is inclined somewhat to its respective disk so that a lip portion may approach and possibly scrape the disk. Since the wheels are located rearwardly of the disk axes, the wheels essentially gauge and scrape where the disks exit the ground and thus compact the soil to form a generally V-shaped furrow with flat upper walls. It is to be noted that raising or lowering the wheels allows the disks to penetrate to a deeper or shallower extent and thus controls furrow depth.
Also to be noted is that when a wheel contacts an obstruction, and the other wheel does not, that the frame can be raised by the single wheel with the disks being supported only by one wheel at that time in cantilever fashion. Hence, the frame and disks will deviate somewhat from the horizontal and not provide accurate depth control. This is not a problem when each wheel is mounted close to its associated disk. This is a considerable problem when the wheels are substantially spaced laterally from the associated disks. Of course, clogging becomes more prevalent then also. If the wheels are not individually supported for rotation the situation is essentially the same. Equalizer systems due in part to elevational limits, also encounter this problem.
Longitudinally, the most accurate disk gauging is achieved by orienting the axes of the gauge wheels colinear with the respective disk axes. But, of course, this would not compact the soil scraped from the disks where same exit the soil.
Thus, the prior art structure generally produces furrows of accurate depth for the seed drop which usually occurs at the point where the disks exit the soil but results in a generally V-shaped furrow with flat upper walls. These walls are usually collapsed on the seed deposited in the furrow by laterally angled firming wheels which cover the seed while not compacting the soil over the seed. Unfortunately the walls and surfaces adjacent the furrow consist of dry soil, with the soil removed from the furrow being compacted and mixed with the dry surface soil, and do not possess as high a moisture content as the soil merely removed from the furrow. Further, in hard dry soils the angled firming wheels require a high spring load which often causes gauging to also occur at the angled firming wheels which adversely affects furrow depth and also the pinch wheels can even lift the seeds above that desired at shallow planting depths.